Methylammoniumhydroxid preparation method

Published by Bender

Yield: 77%
Product: Methylammoniumhydroxid
Reagents: potassium iodide, methanol, Sulfuric acid monohydrate, sodium sulfate
Reference: forum hive

36,6 g potassium iodide and 20 mls water are placed into a 100 ml FBF and plugged w/a 2-hole stopper.

One hole of the stopper is fitted w/a distillation condenser (end immersed into a beaker w/cold water) and into the other is stuck a plastic syringe (SWIA doesn't have a pressure-equalized addition funnel of such size) with 20ml ~82% MeHSO4 (made from 50mls MeOH, 50 mls H2SO4, 24 g Na2SO4).

The mixture is heated on a waterbath to 80-90 C, KI dissolves and addition of the acid is commenced. The mxtr immediately turns dark brown and some H2S is given off. However, it very soon stops and oily drops of MeI appear in the condenser.

The addition was carried for ~5 hrs (SWIM was particularly sloppy that time, adding acid irregularly, at the end sayin 'fuqit' and going to bed - at 4am in the morning), and the theoretically calculated qtty of the acid wasn't enough - total of ~35-45 mls was added. SWIM is certain though, w/the use of an addition funnel, it would take much less time.

Addition of each new portion of acid (usually followed by shaking the flasksmile - OTC mag stirrer, so to saysmile) caused a very visible increase in MeI production, however near the end that effect ceased, and purple vapors began to appear. The distillation was stopped when separation of MeI (and SWIA's patience) almost ceased (however, in the morning there was ~0,3-0,4 mls of the black product under the layer of solidified salt, which SWIA didn't bother to extract).

The yield of the crude product was 10,5 mls, which equals to 77% of theory.


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